It's the biggest UI change in nearly 20yrs, so obviously it's going to take some getting used to. People had the same reaction to the Office ribbon but it was fine when people got used to it. Don't forget that Microsoft will be including a tutorial explaining the new interface, which will take away most of the shock factor that exists at the moment.

I think you're soft selling it quite a bit there, Metro has major usability problems on the desktop that people aren't likely to adjust to. With the ribbon the problem was moving common shortcuts people used, that's a much more simple concept. I've made many adjustments personally but it regularly disrupts my workflow. Maybe in the future Microsoft can improve it but I highly doubt we'll be deploying this at all in its current form.

I'm not really sure why we needed a unified interface anyway, desktop and tablet/mobile interfaces are quite literally at odds in what they are trying to accomplish so it's an awkward shoehorn at its best moments.